Shifting 0-5V signal to -2.5-2.5V

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In summary: Actually I'm working on a laser scanner system for light show with some mirror galvanometers. I don't have a datasheet on them or any type of function generator so having an easily adjustable supply will be great for finding the limits of operation. Thanks for all the posts, its been a great help!In summary, if you have a voltage that varies from 0-5Volts and you want to shift it down to -2.5-2.5Volts, you will need to supply a positive voltage on pin 7 and a negative one on pin 4.
  • #1
bassplayer142
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Shifting 0--5V signal to -2.5--2.5V

I have a DAC coming from my micro with a signal that will vary anywhere from 0-5Volts. What are my options of shifting that down so I can get a -2.5 -- 2.5V swing? Thanks!
 
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  • #2


In a op-amp voltage difference amplifier, you could subtract 2.5V from the input:

diffa2.gif
 

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  • #3


For this setup I will need to supply a positive voltage on pin 7 and a negative one on pin 4 right? thanks
 
  • #4


bassplayer142 said:
For this setup I will need to supply a positive voltage on pin 7 and a negative one on pin 4 right? thanks

Yes, about +5 / -5 volts DC at a minimum.

There may be a much simpler solution but without a more detailed description of the nature of the signal then you mightn't get it.
 
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  • #5


Yes, you need a bipolar power supply. Your circuit is a unipolar to bipolar converter. If interested, I have an article about this type of circuit here:

Design a Unipolar to Bipolar Converter for a Unipolar Voltage Output DAC
http://masteringelectronicsdesign.com/design-a-unipolar-to-bipolar-converter-for-a-unipolar-voltage-output-dac/"
 
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  • #6


From your name, bassplayer, I'm thinking that you have an audio signal?

If it is over 10Hz or so, presuming that the destination is biased around 0v, you might be able to just put a big capacitor in the signal line. You might also get away with using a resistor divider to a negative supply voltage without bothering with an Op-Amp.

What's your actual application?
 
  • #7


Actually I'm working on a laser scanner system for light show with some mirror galvanometers. I don't have a datasheet on them or any type of function generator so having an easily adjustable supply will be great for finding the limits of operation. Thanks for all the posts, its been a great help!
 
  • #8


Then they are pretty much just speaker voice coils, and a inline capacitor will do the trick. However you probably need more power than the PC output can push. Perhaps more than the PC headphone output too, but you could try that or a small powered speaker system for a start.
 

1. What is the purpose of shifting a 0-5V signal to -2.5-2.5V?

The purpose of shifting a 0-5V signal to -2.5-2.5V is to convert a unipolar signal (0-5V) to a bipolar signal (-2.5-2.5V). This allows for a wider range of values to be represented and can be useful in certain applications.

2. How is a 0-5V signal shifted to -2.5-2.5V?

A 0-5V signal can be shifted to -2.5-2.5V using an operational amplifier (op-amp) circuit. The op-amp is configured as an inverting amplifier with a gain of -0.5, which effectively shifts the signal by -2.5V.

3. Why is it important to shift a 0-5V signal to -2.5-2.5V?

Shifting a 0-5V signal to -2.5-2.5V can be important for compatibility with other systems or devices that only accept bipolar signals. It can also be useful in applications where a wider range of values is needed for more precise measurements.

4. Are there any potential issues with shifting a 0-5V signal to -2.5-2.5V?

One potential issue with shifting a 0-5V signal to -2.5-2.5V is the loss of resolution. As the signal is shifted, the original 0V and 5V values will now be represented as -2.5V and 2.5V, leaving only 4 possible values in the range of -2.5-2.5V. This may not be an issue depending on the application, but it is something to keep in mind.

5. Can any signal be shifted from unipolar to bipolar using this method?

No, this method of shifting a signal from unipolar to bipolar only works with signals that have a fixed reference point, such as a ground or 0V reference. Signals that do not have a fixed reference point, such as AC signals, cannot be shifted using this method.

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